Seat structure for trucks



Oct- 21 1958 A. K. sxMoNs ETAL 2,856,984

l SEAT STRUCTURE FOR TRUCKS IIx-l *1.1.3

4 lSheeizs--SheecI 2 A. K. SIMONS ET AL SEAT STRUCTURE FOR TRUCKS Original Filed Aug. 25, 1955 oct. 21, 1958 0t.21,195s l AKSMONS Em 2,856,984

SEAT STRUCTURE FOR TRUCKS IN TORS JVM Oct.- 21, 1958 A, K. slMoNs 'E1-AL 2,856,984

SEAT STRUCTURE FOR TRUCKS Origgngl Filed Aug. 25, 1955 4 Sheets-Sheet 4 Y United States Patent 2,856,9s4 p vSEAT STRUCTURE FoR TRUCKS Original application August 23, 1955,

530,122. Divided and 1957, Serial No. 693,224

2 Claims.

Serial No.

This application is a division of copending application Serial No. 530,122, filed August 23, 1953.

This invention relates to a seat structure and more particularly to such a seat structure designed for use in truck cabs, the seat being shown as an individual seat designed to support the driver of the truck. v

General objects of the present invention are to provide a seat which has superior ride characteristics; which provides the maximum vertical movement of the seat frame without interference and absorbs objectionable jars and vibrations of all frequencies; in which the suspension is arranged below the seat; which is composed of simple parts or sub-assemblies and is adapted to mass production; which is strong and durable in construction and will operate smoothly and easily without damage; which is light in weight; and which is free from projecting parts adapted to injure the rider or interfere with his operation.

A specific object of the present invention is to provide in a seat structure a very simple and eifective mechanism for adjusting the angularity Aof the back cushion with reference to the back part of the frame so that the oper' ator can adjust it to the angularity most suited for his comfort.

, Another object of the invention is to provide a simplified form of base part of the seat structure which includes means for adjusting the seat structure fore-and-aft and which also supports the spring suspension which carries the seat part of the seat structure.

Another object of the invention is to provide a simple and effective means for limiting the upward movement of the seat part of the seat structure and which also deter'- mines the back pressure against which pretensioning of the main springs of the seat structure is effected and also restrains the seat part of the seatrstructure against side` wise lurching.

Another object is to provide a simplified and strong movable frame for a truck seat, the tubular frame being composed principally of formed metal tubes and a stamping and cross bars connecting the bottom parts of said tubes.

Another object is to provide simplified and strong part of the shackles for the linkage supporting the seat seat structure on the base part thereof.

Other objects and advantages of the present invention will be apparent from the following description and drawings in which: l

Fig. 1 is a front elevational view of a resiliently mounted seat structure embodying the present invention.

Fig. 2 is a side elevational view thereof. l

Fig. 3 is a horizontal sectional view taken generally on line 3--3, Fig. 2.

Fig. 4 is a vertical transverse sectional view taken generally on line 4 4, Fig. 3.

Fig. 5 is a fragmentary view similar to Fig. 4 and showing another position of the parts and in particular showing the effect of a pair of double purpose stops, the purposes of these stops being to determine the amount of loading or windup of the springs when the seat is un- Shorewood, and Arthur 0. Radke, f

this application October 15,

Patented Oct. 21, 1958 ICCv loaded and also to prevent side lurching of the seat when the seat is occupied.

Fig. 6 is a fragmentary vertical section taken on line 66, Fig. 3.

Fig. 7 is a horizontal section taken line 7-7, Fig. 2.

The seat structure embodying the present invention is particularly designed for use in the cabs of highway trucks and the like and includes a seat part 10 supported on a base part 11 by a suspension embodying the present inven-r tion. The seat part 10 is shown as including a detachable seat cushion 13 and a detachable back cushion 14 carried by a metal frame. This metal frame is shown as comprising a pair of L-shaped tubular side bars 15, each having a vertical back part 16 which extends alongside the back cushion 14 and a horizontal bottom part 18 which extends under the corresponding side of the seat cushion 13. The bend between the parts 16 and 18 can can be reinforced by an internal tube 17. The forward ends of the horizontal bottom parts 18 of thesey tubular side bars 15 are bent toward each other, as indicated at 19, and a metal stamping 20 embraces these inwardly turned ends 19 and can be secured thereto in any suitable manner, as by Welding. Y

v.T he upper edge 21 of the metal stamping 2 0l is formed to conform to the curvature of the tubular sideframe' members 15 and this stamping has a depending apronfor flange 22 which can be'anged, as indicated at 23, to impart the desired rigidity to this apron. A small L-shaped bracket 25 is secured, as by screws generally yalong 26, to each side of the back cushion 14 at the rear thereof` so as to provide a forwardly projecting ear 28` arranged to contact .the inner side of the corresponding upright back partl16 of the tubular side frame member near the upper extremity thereof. Each ear 28 is joined to this upper extremity by a pivot pin in the form of a 'simplev rivet 29, the pivot pins 29 being in horizontal 'alinement'A so that the back cushion 14 is free to swing about these pivots as an axis.

A feature of the invention residesin the adjustability of the angularity of the back cushion and to this. end a vertical toothed plate 30 is welded to the inside ofeach vertical back part 16 of the seat frame. These .vertical plates project forwardly from the Vertical backparts or tubes 16 of the seat frame and each is provided with a horizontal slot 31 the upper edge of which is indented-to provide a series of detent notches or teeth 32.,A Eachv vertical'toothed plate 3) is provided along its upper edgey with a horizontal stilfening flange 33. A horizontal spring loaded detent rod 34 is journalled on the back cushion 14 and is provided with offset ends 35 which project into the slots 31 and releasably engage the notches 32 formed in the tops of these notches. The

straight central part 36 of this detent rod is journalled. in a pair of strap bearings 37 each consisting of a metal.

seat'frame and one end 42 of this spring isv anchored in' this strap bearing 37 while its other endis formed to;

Y provide a hook 43 which extends under and biases upwardly the corresponding offset end 35 of the detent rod. Accordingly this spring 41 holds the olset ends 35 of the detent rod upwardly into a selected pair of notches, 32 of the side plates 30. When it is kdesiredto alter the.` angularity of the back cushion 14 either offset end 35' of the detent rod is pushed down out of this pair of v 3 notches. The back cushion wards or forwards about the pivot 29 until it is disposed at the desired angularity. The offset end 35 so pushed down is then released so that both offset ends 35 spring up under the influence of the -spring 41 into another pair of the notches 32. i Y

As best shown in Fig. 3, across 4barr44, shownasrbeing L-shaped in cross section, is welded at its ends to .the horizontal bottom parts 18 ofthe tubular side frame members 15.

- This cross bar 44 is arranged in rearwardly spaced relation to the front stamping or apron 20 and carries a pair of forwardly projecting ears-45, each of which carries a horizontal pin 46, thesev pins'extending -outwardlytoward thecorresponding tubular frame member -15. Each of these pins is `shown as riding in a Jshapedl slot 48 provided in the vertical ear 49 of an L-shaped bracket 50, this L-shaped bracket also havinga horizontal ear '51 which is secured, as byscrews 52, to the'under side of the seat cushion 13 at the forward end' thereof. The J-shaped slot 48 has a relatively long upstanding portion 52 at its front end and a relatively short upstanding portion 53 at its rear end. When the pins 46 seat in the upper ends of the relatively long upstanding portions 52 of the J-shaped slots 48, the front end of the seat cushion is supported at a relatively low elevation. Whenfthese pins are supported in the relatively short upstanding portions 53, the front end of the seat cushion is supported at a relatively high elevation. In either case, the seat cushion 13 is capable of swinging about the pins 46 as va fulcrum.

.The rear end of the seat cushion is preferably adjustable to a number of elevations, particularly to determine the angularity of the seat cushion with reference to the horizontal, this angularity being also related, of course, to the selected reclining position of the back cushion 14. For this purpose, a rod 55 extends through the .horizontal bottom parts 18 of the tubular side frame members 15 and is ycapable of turning, this rod being provided at one end with a handle 56 for turning the same. Against the inner face of each of these horizontal bottom parts 18 ofthe tubular side frame members 15,` a plate 58 is secured, as by welding, to the rod. These plates 58 are of generally elongated rectangular form with the rod 55 extendingeccentrically through one corner thereof. It will therefore be seen that the edges 59, 60, 61 and 62 are progressively more distant from the axis of the rod 55 so that by turning the rod to engage the bottom of the' seat cushion with one or the other of these edges, the seat cushion will be supported at a corresponding-elevation. Desirably, these edges 59-62 engage metal plates 63 provided on the bottom of the seat cushion 13 near the rear end thereof.

The base part 11 of the seat structure comprises a pair of spaced horizontal channels 65 which can be secured by screws 66 to the chassis 67, these channels being arranged parallel and extending fore-and-aft and being arranged'below the seat part 10 of the seat structure. Each of these channels has opposite horizontally extending anges 68 which are embraced by reversely bent anges 69 of an inverted channel 70. A series of ball bearings 711are contained within the channels 69 and 70 and permit free fore-and-aft movement of each channel 70 with reference to the corresponding channel 65. Any suitable means (not shown) can be provided for retaining the balls 71 in position.

. The front and rear ends of the channels 70 are'connected to each other by sheet metal cross pieces 75 which are U-shaped in cross section with end channels opening upwardly, each of these cross pieces having relatively high front and rear walls 76, 78 and having a depressed central part 79. These cross pieces 75 form the principal cross members of the base part 11 of the seat structure and anadjustment, indicated generally at 80, is provided 14 can then be'swungback# "'formo'vingand securing these cross channels 75 and the top channel 70 at different fore-and-aft positions along the bottom channels 65. As best shown in Figs. 2 and 3, this adjusting mechanism includes a plate 81 which is secured as by rivets 82, to one of the sliding channels 70 to extend horizontally outwardly therefrom. The outboard end of the plate 81 carries a pivot 83 which supports a latchgmember 84. This latch memberI 84 is provided with a toothv85 which is movable through a 'slot 86 provided in the corresponding movable channel 70. This tooth 85 is arranged to engage one of a series of teeth 88 provided in the corresponding side ange'68 ot the channel 65. A helical compression spring 89 connects theA outer'extremity of the latch member 84 with the sliding channel member l70, thereby to hold the tooth 85 in engagement with any selected tooth 88. A handle 90 is provided for manipulating'the latch member 84, particularly to disengage the teeth 85, 88 and following which the sliding channels 70 can be moved longitudinally along the xed channels 65.

A tubular base pivot-pin is mounted in each end of each sheet metal cross piece 7S, these pins extending fore-and-aft. Forv this purpose, each base pivot `pin 95 is mounted at its ends in the front and rear side walls 76, 78 at the upper, outer'extremity thereof as best shown in Fig. 4. ,These base pivot pins95 can be secured in any suitable manner and each supports a bearing bushing 96` at'the upper end of a shackle 98, thrust washers 99 being also preferably provided at the opposite 'ends'of each bearing bushing 96.

The shackle 98is preferably made of sheet metal to be U-shaped or channel shapedin cross section,having a cross back part 100 and parallel vside flanges or walls 101 through Which'the bearing bushing 96 extends and to which this bearing bushing is secured. The oppositel or lower end of the shackle similarly has secured thereto a'bearing bushing 102 in which is journalled a crank armY pivot pin 103. This crank arm pivot pin is fast to the outer .end of a crank arm 104, the inner end of each crank arm 104,beingfast to a fulcrum rod which extends fore-and-aft. An important featurelof the invention resides in the provision of a stop 104' projecting from the outer end of each crank arm 104 and which in the position of maximum elevation of the seat part of the seat structure (illustrated in Fig. 5) engages the corresponding edge of the back part 100 of the shackle 98. These four stops 104' not only limit the upward movement of the seat when unloaded, but also limit the lateral movement of the seat when loaded so as to prevent sidewise lurching of the seat.

As best shown in Fig. 6, each end of each fulcrum rod is journalled in a bearing bushing 108, 109, the back bearing 109 being tted in a boss 110 projecting forwardly from a plate 111, this plate 111 being removably secured, as by bolts 112 (Fig. 3), to the vertical ilange ofan L-shaped cross bar 113 connecting the ends of thevertical parts 16 of the tubular side frame members 15. Each bearing bushing 108 is tted in a hole provided in the L-shaped cross bar 44 and a washer 115 can be welded to this cross bar around this hole so as tofprovide adequate support for the bearing bushing 108. Intermediate this cross bar 44 and the front stamping or apron 20, each fulcrum rod 105 connects with a rubber spring 106, these rubber springs providing the resilient support for theseat part of the seat suspension.

Each of these rubber'torsion springs can be of any suitable construction and is'shown as comprising a cylindrical vtubular rubber body 107 having a ilat face 109' at one axial end and having a concave face 110 at its opposite axial end. To the outer -ilat face 109 of each rubber body 107 is vulcanized a metal disk 111 having a hub 112 which ts the adjacentend of the corresponding fulcrurn rod 105V and'can be secured thereto inany suitable manner as by the cross pin 113 shown. To the gesagt-i4' opposite concave face V11,0'V of each rubber body is vul- Vcanizedka conforming convex metal anchoring plate or memberv115, this anchoring plate having an outwardly projecting ear 116. This anchoring plate also has a tubular hub Y116 journalled on a pin 117, the latter projecting from` the depending apron or ange 22 as best shown in Fig. 6.

A nut 118 is fitted against each of these ears 116, this nut being provided with a stem 119 which extends through the companion ear 116 and is secured in this opening by a pin 120. An adjusting rod 121 has oppositely threaded ends 122v`and 123y each of which is respectively screwed into the corresponding nut 118. One end of this rodis extended and is formed to provide a handle 125.by means of which the rod 121 is turned toadjust the anchoring plates 115' of therubber springs 106 in unison. The opposite ends of the adjusting rod 121 and the nuts 118 are, `of course, reversely threaded.

To minimize sidewise tipping or lurching -of the seat part 10, the two fulcrum rods `105 are interconnected so as tov rotate in unison. The connection between these two fulcrum rods is shownas being in the form ofy a link 130, pivotally connected at its opposite ends to the metal disks 111' of the two rubber springs 106.V For this purpose, each of these metal disks 111 has mounted thereon apin 131 whichextends through an opening in the' corresponding end of the link 130 and also carries a cotterpin 132'which. retains the link on the pin.4

A bottoming cushion 135 isy secured in the centerof each of the channel shaped sheet metal cross members 75,' these being in` position to engage the fulcrumed ends of the crank arms 104 when the `seat part fully bottoms.

To calibrate the amount of pretensioning of the springs 106, the front apron can be provided with a horizontal sight opening 136 in line With the nuts 119 and this nut can carry a Vertical mark as shown in Fig. l. This mark cantraverse 'a calibratedscale 138 above `the sight openmgf Li Assuming the normal loaded position of the seat illustrated in Figs. 1 through 4 and 6, in the operation of the suspension, the upward movement of the chassis or body 67 of the truck, through the stationary channels 65, balls 71, adjusting channels 70, channel shaped cross pieces 75, and shackles 98 moves the outer or free ends of the crank arms 104 upwardly. This rotates the fulcrum rods 105, these fulcrum rods rotating in their bearings 108, 109, the bearings 108 being mounted on the vertical ange ot the cross bar 44 of the seat part 10 of the seat structure and the bearings 109 being mounted on the cross bar 113 through the removable plate 111 which is secured to the cross bar 113 to project downwardly therefrom.

The oscillation of each fulcrum rod 105 is resisted by the corresponding rubber spring 106, this movement being transmitted through the pins 113 to the disk 111' vulcanized to the at rear face 109' of the rubber body 107 of each rubber spring, Since the forward end of each rubber body 107 is vulcanized to the convex anchoring plate 115', the torsional force imposed on each rubber body 107 by its fulcrum rod 105 is transmitted to the downwardly extending ears 116 of these convex metal anchoring plates 115. These two ears 116 are adjustably connected together by their swivel pin-nuts 118, 119 and the reversely threaded screw 121 in these nuts and hence it will be seen that these connected ears 116 provide a non-rotating anchorage for the forward ends of the rubber springs 106. When it is desired to increase the pretensioning or windup of the springs, the threaded rod 121, through its handle 125, is turned in a corresponding direction. If the seat is not occupied at the time of so adjusting the pretensioning of the rubber springs 106, the back pressure against which this pretensioning is made is supplied by the stops 104 at the outer ends of' the crank arms 104. Thus, the torsional force of the rubber springs 106 tends, of course, to lift the seat part'10 and to bring the' crankrms 1'04'and links 98 tothe position shown in Fig. 5 in which the stops`104 engage the cross parts of the`shackles 98. Since the parts cannot be elevated above thevposition shown in Fig. 5, further turning of the handle to increase the tension of the rubber springs 106 merely serves .to increase the pretensioning or windup of the springs.l The degree of windup is indicated by the mark on the nut 119 (Fig. 1) traversingthe calibrations 138.

Lateral tipping of the seat part 10 is minimized by the link interconnecting the end, plates 109 of the two rubber springs 106. 'Ihis link pivotally connects these end plates 109 to rotate in unison and vsince, these` end plates are fixed to the two lfulcrum ,rods 105 bythe pins 113, this link compels the two fulcrum rods 105 to rotate in unison. It will be noted bythe-.positioning of the link 130 as shown, the swinging movement of one pairy of crank arms' A104 can occur, onlyl when there -is a corresponding movement ofthe fother pair'of'crank arms 104.

At the Sametime, theseat part10 `is-capable of'lateral movement which is permitted .by the shackles 98.

When the `seat part 10` so moves downwardly `relative to thebase part 11 from the normal loaded position showninnFigs. 1 through 4 and .6, or, whenthe base part 11 is forced upwardly relative to the seat part 10, the eiective opposing forceofthe` rubber springs 106'Yincreases ata geometric and` not at an arithmetic rate. In this, particular.` case, the geometric Irate of change of resilience is of the accelerated increase type in which incre-` ments of vertical movement of the base part are vopposed by an accelerated rate of increase'of resilient resistance. Thisfis due `tothe progressive decrease inthe effective leverage of. the Ycrank/arms 104 Vas theyrswing-from thei position ,shown in Fig. 4 about theinfulcrum rod axes'of rotation. This action. is also influenced by the fact that increments of vertical displacement of the outer ends of thecrankarms 104 cause accelerated rates of increasein the angular displacement of the' rubber torsion spring 106. This latter is due to the fact that increments of vertical movement of the outer ends of the crank arms 104 are not proportional to the accompanying increments of angular twist to which the rubber springs are subjected.

This geometric action also occurs when the base part 11 moves downwardly relative to the seat part 10 from the normal loaded position shown in Figs. 1 through 4 and 6. Throughout this particular movement, the geometric action is of the accelerated decrease type, that 1s, as the base part 11 passes through increments of downward movement, the rate of decrease Iof the resilient force tending to push the seat part downwardly increases.

By this means, so far as Vertical forces are concerned, the seat part 10 is free to oat along solely under the influence of gravity (plus whatever vertical momentum forces are present), this feature being of particular significance when it is realized that the occupant is also, at this time, solely under the inuence of gravity (plus whatever vertical momentum forces are present). The conse quence is that within this particular range of movement, the occupant vof the seat moves vertically up and down with the same acceleration and deceleration as the seat part 10 and hence without changing the pressure between the occupant and the seat. Such a desirable result is quite different from that obtained from conventional seat suspension means in which the vertical force jerks the seat down whenever the strain imposed on the seat part is negative. With the present seat suspension means, no such forces tending t-o pull the seat part downwardly are possible. v

It will particularly be noted that the stops 104', in addition to limiting the upward movement of the seat part 10, as illustrated in Fig. 5, and hence providing the back pressure against which the pretensioning of the rubber springs 106 is effected, also serve positively to limit lateral movement or lurching of the seat part particularly when the seat-part isin an elevated position.

' 'It will alsobe seen thatthe angularity of'both the back andtheseatpcushions '14 and ,13 can'easily be adjusted to suit the driver. Thus by pushing down either oiset end 35 ofthel detent rod journalled on the back cushion part 14 the opposite oiset ends 35 are pushed'down out of the corresponding pair of notches 32 ofV the side plates 30. The ba'ck cushion 14 isy then swung to the "desired angularity about the pivots Z9 and'theroiset end 35 so pushed down isreleased. 'Bothyofseten'ds 35 of the detent rod then spring up underfthe Ainuencer'rf the spring 41 into anotherl'pair of the notches 32 to hold the back cushion atlthe selectedangularity. Since the seat cushion 13 is pivotally supported at its'front end by the pin 46, turning the'handle '56.to rotate the eccentrically ,supported plates 58'wi1l'progressively 1bring" the'fedges' 59, 6061 and 62 of these plates 58 into supporting engagement ,Withthe bottom ofthe seat part. Since these edges areatprogressively increased distancesv from the ofrotation of these plates 58, this adjustrnent'serves ktograise andlower the back part oftheseat cushion `131.

"It, willalso be noted that' the front end of. the-seat cushion113 Vcan be'ac'justed t-o twoidifferentelevations .by virtuezofthe 'J'shaped s1otsj`48 `in `their dependingbrackets 49. v A

"From the"foregoing, it WilLbe seenthat'thepresent invention provides a seatwhich in particular is fully adjustable'throughout, including' its fore-andfaft position, the elevation and =angularity of the seatcushion, with reference-to the vertical, of the back cushionand the degree "of pretensioning of the rubber` torsionsprings. It will further be seen that the seat can be madeto operate in ahighlydesirable frequency range regardless of-fthe Weight lofthey occupant .and thatat thersame time, the seat structure is rugged in construction andlovvincost.

`We claim:

1. A seat structure comprising apair of seat frame sides,

each having a horizontal bottom part and a vertical part arising from the rear'end of the bottom'fparg a metal stamping connecting the frontends of-said horizontal bottom parts and forming a dependingvapron, spaced front and rear cross bars connecting said frame sides, a-pair of laterally spaced fore-and-aft fulcrum rods journalled in said cross bars-and each having afpair of arms'extending generally horizontally in opposite directions With referencefto'the other pair of arms, a bafse part, ashackle member connecting the outer endof each armwith said base part, a rubber body` at the front end; of each fulcrum rod and arranged in the space between said apron and the front cross bar, `means securing the front end of each fulcrum rod to the adjacentend of the adjacent rubber body, a platetast tothe other end of each rubber body, means journalling each of saidplates on said apron, and means'adjustably securingrfsaid plates of .both rubber bodies together.

2. 'In a seat structure having a basepart, a seat part, a plurality of transverse lever arms fulcrumed on one of said parts and spring means resisting movement of said lever arms; the combination therewith of a shacklefpivotally connecting the-free end'of each lever arm with the other of said parts and eachcomprising a piece of sheet metal lof U-shaped formrin cross section to have a cross References Citedin kthe tile of thispatent UNITED STATES PATENTS Sampson Aug. 6,11918 Hickman June 29, 1954 

